Polishing gems.



S. M. SGHENKEIN.

POLISHING GEMS.

APPLICATION FILED 11017.17, 1911.

Patented Mar. 23,1915.

wi/tmeooeo SAMUEL M. SCHENKEIN, OF NEW YORK, N. Y.

POLISHING GEMS.

Application filed November 17,1911. Serial No. 660,861.

To all whom it may concern:

Be it known that I, SAMUEL M. S HEN- KEIN, a citizen of the United States, residing at' New York city, New York, have invented certain new and useful Improvements in Polishing Gems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention has relation to the polishing of gemsand more particularly to the polishing of diamonds, and has for its object to accurately and properly hold a gem to be cut, to permit the relative rotation of the gem into grinding position for successive facets, and the inversion of the gem, while maintaining the out facets inthe same angular relation to the holder or support, thereby enabling the cutting of thefacets on opposite sides of the girdle of the gem exactly opposite to one another.

I am awarethat various mechanisms have been employedin the polishing of diamonds with a view to accomplishiilg these results, but none of said mechanisms have, up to the present time, given more perfect results to.

the finished stone than the hand-dop, where the positioning of the facets on the stone lies wholly within the judgment of the polisher.

I believe that I am the first to actually polish a diamond where the degree of inclination of the sixteen primary facets of a brilliant as predetermined by-thc operator, may be obtained by mechanical means, and movement of the mechanism in conjunction with-a fixed scale; and also to place eight of these primary facets above the girdle so that a they are exactly opposite the eight below the girdle, and furthermore to make the sixteen girdle facets above thegirdle so that they are directly opposite to the sixteen girdle facts below the girdle, and also to obtain for the table and culet an exact flat polished surface that is parallel to the plane of the girdle. This has been the aim of diamond polishers for many years, for the reason that the exact symmetry of the upper and lower portions of a cut diamond with respect to its axis of symmetry greatly increases its brilliancy.

Many of the apparatuses heretofore employed depend upon cement of some sort for holding the gem in position, but I have found by practical experience that there is no cement (and I have tried all kinds that I could obtain) which will hold a diamond in' its. support until the entire upper or lowerportion has been completely ground and polished. I find that the excessive heat, generated by the friction of the grinding Wheel on the stone, is sufficient to destroy or remove the cement-after the grinding of two or three facets. The stone then drops from its seat, if cement alone is used to hold it, or if the cement is aided by a mechanical holding devlce, then as soon as this device is removed the stone drops out, and it is a practical. impossibility to properly re-seat the stone in its holder so that the other facets to be ground .will be. symmetrical with those already ground. 7

Referring to the drawings, in which like parts are similarly designated Figure 1 is an assembled View, partly in section, of the means for holding a diamond during the grinding and polishing operation. 'Figs. 2, 3, 4 and 5 are perspective views respectively, of the clamping collar, gem retainer. gem support and gem support holder. Fig. 6 is a sectional View of Fig. 5, showing centering means. Fig. 7 illustrates an implement, to be used in connection with the gem support, for accurately transferring a holder, preparatory to the cutting of a new facet. Fig. 10 is a plan view showing the circular opening in the gem retainer and made twice the actual size of a retainer such as I have been using.

Referring now to the assembled view shown in Fig. '1. and to Fig. 4, the gem support comprises a gem holder or pot 1, preferably, but notnecessarily, conical. in form, provided at its base with a central cylindrical boss 2, of smaller diameter than said base, and which terminates in a screw shank 3, preferably, but not necessarily, of less diameter than the boss 2. At the top of the gem support, in the apex of the pot, is a gem-receiving recess 4, which recess coma loose gem-ejector pin 6.

municates with a central bore 5 in which is preferably provided with a hole 7, Fig. 1, for the insertion of a capstan pin for unscrewing and removing the pot when desired, or for replacing another support having a recess 4 of dinerent size for a different sized gem. The pot 1 is screwed into an adjustable center, comprising a head 8, a central boss 9, and a screw shank 10, all preferably of different diameters and preferably made in one piece. The head 8 of the adjustable center seats on a flange 11 of an annular member 12, the boss 9 being somewhat less in diameter than the central opening 13 in said inwardly directed flange 11, so as to be free to move laterally therein. Three or more radial screws 14 in said flange engage the central boss 9 for simultaneously ad usting the center and the pot l secured thereto, with respect to the annular member 12. The heads of these screws are countersunk. Before adjustment, the center is secured to the annular member 12 by a nut 15 that seats on said flange 11. A screw 16 passes centrally through shank 10 and boss 9, and engages the end of the headed ejector pin 6.

The assemblage just described, and shown in perspective view in Fig. 4, is provided with a radial pin -17 projecting from the annular member 12 that is positioned to engage in any one of thirty-two radial slots '18 in the tubular portion 19 of the gem to a circular plate 21 by means of screws 22 passing loosely through holes 23 in said plate. The flange 20 and plate 21, as shown in Fig. 5, are provided with registering marks a whereby the member 19 may be adjusted slightly with respect to plate 21. Plate 21 is provided with ears 24 having circular ends concentric with their perforation 25. These ears form a fork that embraces a supporting lug 26, Fig. 1, forming part of any suitable carrier, and to which said ears are clamped by means of a bolt 27 and thumb-nut 28. The lug .26 is provided with a zero mark I) and the circular ends of the ears 24 are graduated with respect to said mark, as shownv at c and. 0, Figs. 1 and 5. To indicate the degree of angularity between 26; and 21, and consequently of all parts connected to and carried by 24, the odd degrees are, for convenience, marked on one of said ears at c and the even degrees on the other at 0, however, it is obvious that all of the graduations may be marked on one of the ears only.

After the gem support. Fig. 4, has been placed in the gem support holder, Fig. 5, the gem having been previously mounted in the The pot 1 is a shoulder 36? and provided with diametrical slots 31. These slots receive two lugs 32 on the gem support holder, said lugs being projections of two of the teeth formed by the thirty-two slots 18 in the end of the tubular member or socket 19. The plate 30, Fig. 3, being a sector, extends preferably to a point just a little beyond the center, and there is a circular opening 33 near the apex of said plate terminatingin points 31, which grasp and engage the gem just beyond the center. Heretofore it has been practised or proposed to retain the diamond to be cut in its seat or cavity in the dop acting as one point of contact with the diamond, by means of two fingers, each finger acting as a point of contact on top of the stone. Only the large facets of comparatively large diamonds can be cut by this three point contact method of holding the stone. Small diamonds or chips cannot be cut at all by such a method, and for these reasons I use a method of holding the stone to its seat in the pot by means of a retainer having an opening therein in the form of a segment of a circle, said segmental opening having an area greater than a semi-circle so that there will be a free space between the ends of the arc. The bottom edge of the opening 33, engages the upper surface of the gem at points between the ends of the arc bounding the opening and back of that portion exposed for grindingand holds it in its seat 4.

It will thus be seen that I do not hold the gem to its seat in a pot or dop at three points only, but have a retaining edge that is over half a circle, thus engaging the stone both forward of and back of its center efiectually preventing the rocking of the stone on its seat under all conditions of operation. The gem retainer, Fig. 3, is held in place by a screw collar 35, Figs. 1 and 2, said collar being provided at its upper end with a flange 36 that engages the shoulder 36 on the gem retainer and forces the flange 60 down onto the upper ends of the teeth formed by the slots 18, the lower portion of said collar 35 engaging a threaded portion 37 on the socket 19. The lugs 32 and cooperating slots '31 prevent any possible rotation of the gem retainer during either the removal or the positioning of the same.

The operation is as follows: The rough gem is forced into recess 4, which. is supplied or lined with solder or equivalent soft metal that can be deformed to an accurate seat, conforming to the surface of the gem, and is held in place, after the seat is formed, by cement. These gems in the rough come provided with a line or cut indicating where the girdle isto be in the finished stone. The gem support, Fig. 4, with the gem 1n 1ts solder seat, is then placed in a lathe or equivalent device to determine Whether the facet is then ground on the stone above the girdle, whether it be the upper or the lower face of the stone. It is customary practice to now grind the diametrically opposite facet, and in order to do so it is necessary to remove the gem retainer and shift the gem support, Fig. 5, 180, in order to bring the pin 17 into the diametrically opposite slot 18. It is an absolute necessity in order to properly effect these operations of trans.- fer or shifting, to have some means for tightly holding the stone to its seat while removing the gem retainer and shifting the support, and there must be a cooperat on between the gem retainer and the holding means, both simultaneously acting on the gem to hold it to its seat previous to the loosening of the collar 35, for the removal and .shifting of the parts. To this end I provide a clamping member cooperating with the gem support or pot, Fig. 1, comprising the device shown in 9. This device consists of a yoke member or foot 88 adapted to embrace the boss 2 immediately below the base of the conical pot 1 between it and the center 8. This yoke member is provided with a post 39 to which is secured an overhanging arm 40 provided with an eye 41 in which engages a screw 42 having a milled head 43 and an engaging pin 44. This pin 44 directly engages the upper end of the stone, or if the table or culet has been cut, it engages the table or culet that is uppermost. The pin 44 is screwed down hard on the stone, thereby clamping the stone in the support. whereupon the collar 35 and gem retainer 29 may he removed with impunity. The entire gem support, Fig. 4, with the clamp in place, is then raised from the gem support holder, Fig. 5, and rotated The parts are then replaced and the gem again clamped by the gem retainer. The clamp. Fig. 9. then removed. and the new facet is cut and polished. This operation is repeated for the cutting of'each new to invert the-stone and to so invert it that every facet on the opposite end of the stone will be directly opposite its corresponding facet on the previously cut end. Heretofore it has been impossibleto do this, so that experts inthe trade recognize it as an almost impossibility, but by my improved method of grinding and polishing diamonds the facets on the upper end are directly in register or symmetrical with those on the lower end-of'the gem, so that the girdle presents a regular figure of thirty-two sides perpendicular to the major axis of the gem. After one end of the gem has been cut, be it the upper or lower end, I cement or, glue the stoneabout the girdle to the pot 1. I allow this glue to become dry, andthen 7 remove the gem retainer and gem support, Figs. 3 and 4, and place the gem' support in a transfer member, Fig. 7. This transfer member comprises a cylinder or tube 45 having an internal diameter the same as that of-the annular member 12, provided at each end with diametrically opposite slots 46 extending a short distance from the ends of the tube toward its middle. The ends of the tube are externally threaded, one end being provided with a screw cap 47 and the other end'with a screw cap 48. This latter 100 cap, 48, has a central threaded boss 49 through which passes a compressing screw 50. In each end of the cylinder I provide accurately fitting'plugs 51, and at the middle'of the cylinder I provide anopening or window 52, at each side thereof. The manner of inverting the stone is as follows: I removethe screw caps 47 and 48 and the plugs 51, and place the support, Fig. 4, with the diamond cemented thereto as above described, in one end of the tube 45, say in the lower end, as shown in dotted lines in Fig.

-7, the pin 17 being guided in the slot 46.

I then place a plug 51 therein and screw the cap 47 in place. In the other end of the cylinder I place a holder whose recess 4 has previously been supplied with soft solder,

so that its pin 17 will be guided in the upper slot 46, but diametrically opposite to the one in the lowerend. Plug 51 is placed on top of this second support, cap 48 is screwed in place and the screw 50 turned to force the diamond into the new metal seat, after which, and while the gem is tightly held between the two supports, I placeglue or other cement around the gem and the sec-' ond pot, having access thereto through the openings or windows 52. The tube is inverted and the lower cap 47 and plug 51 are removed and a. screw driver inserted in screw 16; this screw is then turned, forcing the central, headed, ejector pin 6 against the stone, thereby lifting the whole support,

Fig. 4:, from the stone and transferring the stone completely to the second support, breaking the cement that held it to the first support. This second support is then placed in the support holder, Fig. 5, with the pin 17 registering in the slot according to which the last facet on the opposite end of the stone was cut, or otherwise, as maybe desired. Ihe slots are preferably numbered alternately, for convenience in placing the pins therein.

I claim- 1. A gem support including a gem holder or pot, means for adjusting the pot to center the gem in the support and an annular member supporting said centering means.

2. A gem support having a central ejector pin.

3. A gem support having a central ejector pin and means for forcing the pin gradually against the gem.

4:. In combination, an annular member, centering mechanism carried by the annular member, means to clamp the centering mechanism to said member before the centering operation, and a gem holder or pot secured to the centering mechanism.

5. In combination, an annular member, centering mechanism carried by the annular member, means to clamp the centering mechanism to said member before the centering operation, and a gem holder or pot removably secured to the centering mechanism.

6. In a gem support, a conical pot having a gem seating recess at its apex and a longitudinally movable ejector pin Within the pot and whose end enters said recess.

7. In combination, an annular member having an inwardly projecting flange, radial set-screws in said flange, a center resting on the flange and having a central threaded boss lying within thefiange and engaged by said set-screws, a clamping nut on the boss and seating on the flange, a pot detachably secured to the center, said pot and center having alined bores, an ejector pin loose in said bores, a screw in an end of the center and bore therein to retain the pin in position and to impart to the pin its ejecting movement.

8. In combination, a gem support and a gem retainer comprising a sectorrshaped plate having a pair of retaining fingers with a circular cut-away portion between them and means to hold the support and retainer in operative relation.

9. In combination, a gem support and a gem retainer having a sector-shaped plate having a pair of retaining fingers at its apex with a circular opening between them,

a flanged base, a cylindrical connecting portion between the base and plate and means to hold the support and retainer in operative relation.

10. In combination, agem support having a radial pin, and a gem support holder having as many slots in its end as there are facets to be cut, a member to which said gem support holder is pivoted andmeans to indicate the angularit'y of the support to the member.

11. In combination, a gem support having a radial pin, and a gem support holder having as many radial slots as there are facets to be cutlon oneend of the gem, perforated ears to which the holder is attached, a member between said ears, a pivot bolt passing through the ears, and member, to clamp the support to the member, and indicating means on the ears and member to indicate the angular positions of the holder.

12. In combination, a gem support, a removable gem retainer, and auxiliary means cooperating with the support to clamp the gem to the support during thepositioning, the removal, and the replacing of the retainer.

13. In combination, a supporting means, a removable retaining means and a, removable clamping means cob'peratingwith the supporting means to allow of the removal and replacement of the retaining means without altering the position of the article in the supporting means.

1%. In combination, a gem support including a pot having a boss of less diameter c than the bottom of the pot, a clamping member having a yoke engaging the boss and bottom of the pot, and a clamping screw to engage a gem in the top of the pot.

15 The combination with a gem support of a gem retainer having a gem retaining plate containing an opening, the bottom cir cular edge of which engages the gem both back of and in front of its center.

16. In combination, a cylinder having diametrically opposite'slots at its ends, a gem support, having a radial pin, in each end of the cylinder, each pin being guided in a slot, ejector mechanism for one of the supports, means to close the ends of the tube or cylinder, and forcing means passing through one of the cylinder end closing means.

17. In combination, a cylinder having dianmtricall'y opposite slots in its ends and one or more windows intermediate its ends, a gem support, having a radial pin, in each end of the cylinder, each pin being guided in a slot, ejector mechanism for one of the supports, means to close the ends of the cylinder and a forcing screw passing through one of the cylinder end closing means.

18. The combination with a gem support,

of a gem retainer having a gem retaining plate terminating in two fingers formed by a circular opening through the plate, the lower circular edge of said opening between the fingers engaging the gem to retain it inits seat.

19. A gem supporting member, provided with a gem seat in combination with a gem retainer and means to secure the retainer in operative relation to the supporting member including means'to permit the longitudinal movement of the retainer while preventing rotation thereof during the securing and releasing operation;

20. A gem support and a gem ejector cooperating With the support to eject the gem, said ejector arranged for direct contact with the'gem in 'the support. I

21. A gem support and a gem ejector movable longitudinally of the support, said ejector forming a partial seat for the gem and in direct contact therewith.

22. In combinatioma guide, a-gem support movable along the guide-and means to hold the support against circular displacement While moving along'theguide,'-a second gem support directed toward the first gem support and similarly. guided along the guide, to receive the exposed end of the gem.

23.,In combination, two gem supports or pots, one of which carries the gem having a. faceted end,'and the other gem support being empty, and mechanical means to coaxially' position the pots and insert the faceted end of the gem in the empty pot in angular relation to said second pot similar to its angular relation to the first pot.

In testimony that I claim the foregoing as my invention, I have signed myname in presence of two subscribing witnesses.

SAMUEL M. SCHENKEIN.

Witnesses NELsoN L. KEAcI-I, ALEXANDER HEYERT, 

